1. Field of the Invention
The invention concerns an investment casting process, and in particular an investment casting process wherein a lost pattern is formed in a temporary mold.
2. Description of the Prior Art
The present invention offers substantial improvements in the investment casting processes, those being: "Lost Wax" and "Temporary Pattern" by freezing a liquid in an elastic mold. Both of these processes allow for the manufacture of high quality castings, however, each process presents a number of disadvantages.
The main disadvantages of the "Lost Wax" process originate in the transformation and handling of the used wax for the manufacturing pattern. The high cost of the necessary tooling for the injection of the wax makes this process profitable only for pieces to be manufactured on a large scale. The complexity of the handling of the wax patterns results in a high cost for labor in the preparation of clusters or multiple patterns. There is also difficulty associated with using, and a decline in the quality of, the wax when it is recycled.
When using the "Temporary Pattern" process, wherein the temporary pattern is formed by freezing a liquid in an elastic mold, and the temporary pattern is coated with a ceramic material, the goal is the production of precise parts with thin wall thickness and intricate shapes. Accordingly, the main disadvantages of this process are:
1. the enormous difficulty in the extraction of the temporary pattern from the elastic mold without causing any cracks in the pattern when thin walls must be obtained; PA1 2. the difficulty of manufacturing pieces that require complex cores, which leads to the imperative use of ceramic cores, hence incurring an increase in the price of the final product; and PA1 3. difficulty in the extraction of complete clusters from the elastic mold without causing any cracks. PA1 1. the manufacture of all types of cast pieces, including those which are extremely thin or that require complex cores, while avoiding both the risk of cracking and the need of using cores during the process of pouring the metal; PA1 2. the manufacture of all types of high quality pieces regardless of their complexity, which can be manufactured in large, medium and short runs, with a minimum investment in tooling which makes for a profitable manufacture of such complex pieces in large, medium and short runs; PA1 3. the manufacture of all types of high quality pieces using recyclable materials in the manufacturing of lost patterns and molds which entails low preparation costs of lost patterns and molds; and PA1 4. the manufacture of all types of high quality pieces even when it is necessary for the preparation of complete clusters (multiple patterns) with no risks of cracks, which entails low handling costs of the lost patterns.
With the present invention, the foregoing disadvantages of the prior art investment casting processes are overcome and remedied. A precise casting process is provided by means of a ceramic coating of a lost pattern, in which, unlike the prior art processes, the lost pattern is formed in a temporary mold, which may, be partially or totally lost. The present invention provides the following advantageous effects: